![]() |
| Model Walrus class boat at sea. |
| On this page, a boat made
by Harry Grapperhaus is presented. Harry has been building model submarines
for over fifteen years and has constructed an American nuclear sub and
three Dutch boats: Dolfijn, Zwaardvis and Walrus class. In this page the
building of a Walrus class boat is treated. The boat is approximately 1.6
m long and weighs about 30 kg. The boat dives using compressed air and
has an onboard air compressor.
All pictures on this page
were taken by Harry Grapperhaus.
|
![]() |
| The bulkheads being cut-out in balsa wood. |
![]() |
| The bulkheads are fitted on a wooden broomstick. In this way the complete model can be rotated, very handy. |
![]() |
| The model cut open, approximately at the water line. In the bottom part, all of the balsa bulkhead have been removed. Aluminum bars were glued in to keep the hull into shape. |
![]() |
| The receiver, a switch, and two multiswitch units in the back. |
![]() |
| Pressure gas bottle (blue, 1.5 L, 7 bar) and compressor in the back. |
![]() |
| The electric motor and shaft to the screw. On both sides two rods to control each of the four cross planes. |
![]() |
| The beautiful brass screw and the cross planes. |
![]() |
| The sail of the Walrus model. |
![]() |
| Details of the sail showing the periscopes and masts. |
![]() |
| Schematics of the pressurized air system Harry uses in his boat. The system consists an air compressor, pressure tank, and 13 (!!) solenoid valves that are used for dive control and to operate the masts and torpedo tubes. |
![]() |
| Block diagram of the fail-safe system Harry has designed. The system operates the emergency buoy, the air compressor, vent and blow valves and a safety venting system. For example, (1) the compressor automatically starts if the boat is surfaced and the system pressure is too low and (2) if the signal from the receiver is lost, a emergency gas valve is opened and the buoy is released. |
![]() |
| Details of the fail-safe system. Above: electronic schematics Below: (left) the separate prints (right) the assembled prints sticking out of the submarine. |
![]() |
![]() |
| Harry explaining Sytse how to build a submarine at the U-Boot meeting in Koln, September 2000. |
![]() |
| A proud Harry Grapperhaus and his Walrus. |